Effects of dietary lipid composition and inulin-type fructans on mineral bioavailability in growing rats.
OBJECTIVE
This study reports the effects of feeding with a combination of inulin-type fructans (ITF) and fish oil (FO) on mineral absorption and bioavailability as part of a semipurified diet offered to rats.


METHODS
Male Wistar rats (n = 24) were fed a 15% lipid diet (soybean oil [SO] or a 1:0.3 fish:soybean oil mixture [FSO]) and diets containing the same sources of lipids supplemented with 10% ITF (Raftilose Synergy 1) ad libitum for 15 d. Feces and urine were collected for mineral analyses during the last 5 d of the test period. Fatty acid composition was determined in liver and cecal mucosa homogenates. Liver and bone mineral analyses were performed by atomic absorption spectrophotometry. Bone biomechanical analyses were evaluated by a 3-point bending test.


RESULTS
Compared with the controls, ITF-fed rats had enlarged ceca and a significant decrease in cecal content pH (P < 0.001). The apparent mineral absorption was improved in these rats, and this effect was enhanced by dietary combination with FO for all minerals except for magnesium. Addition of ITF to the diet resulted in higher bone mineral content (calcium and zinc) and bone strength, but increased bone mineral content was only statistically significant in FO-fed animals. A decrease in liver iron stores (P = 0.015) was observed in rats fed FO, considering that ITF consumption returned to levels comparable to the SO control group.


CONCLUSIONS
These findings confirm the positive influence of ITF on mineral bioavailability, which was potentiated by addition of FO to the diet.
Lobo
Alexandre Rodrigues
AR
Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
Filho
Jorge Mancini
JM
Alvares
Eliana Parisi
EP
Cocato
Maria Lucia
ML
Colli
Célia
C
D000818:Animals; D001682:Biological Availability; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism*; D002432:Cecum / Q000187:drug effects / Q000378:metabolism; D004032:Diet; D004041:Dietary Fats / Q000494:pharmacology; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D005243:Feces / Q000737:chemistry; D005395:Fish Oils / Q000494:pharmacology*; D005630:Fructans / Q000494:pharmacology*; D007408:Intestinal Absorption / Q000187:drug effects; D007444:Inulin / Q000494:pharmacology*; D008297:Male; D008903:Minerals / Q000493:pharmacokinetics* / Q000652:urine; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D016482:Urinalysis
D004041:Dietary Fats; D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D005630:Fructans; D008903:Minerals; D007444:Inulin